Am 26.06.2013 um 05:14 schrieb Bharata B Rao <bhar...@linux.vnet.ibm.com>:
> On Tue, Jun 25, 2013 at 01:39:11PM +0200, Kevin Wolf wrote: >> >> Can you please review for the gluster, rbd, sheepdog and ssh driver >> whether it's safe to assume that the image reads back as zeros after >> bdrv_create? > > Gluster supports both file and block backends. While the above is true for > file backend (which uses ftruncate), the same is not true for > block backend (which uses lvcreate & lvresize). > > So overall it is not safe to assume that an image on GlusterFS volume > reads back as zeroes after create. Okay, so for safety we have to return has_zero_init = 0. Erroneously assuming a device is zero initialized can bring severe filesystem corruption. Do you see a way to query the information of the underlaying backend from the storage and return 1 or 0 conditionally? Peter
